In various industrial operations, reactor vessels are employed wherein gases and liquids must be contacted in order for a desired chemical reaction to proceed. Typical of these operations are hydrofining of oils, hydrocracking of the hydrocarbons into lighter compounds, hydrogenation of olefins and aromatics and oxonation of olefins to aldehydes. For the best results to be achieved in the reactor it is essential that the gas and liquid mix thoroughly, be distributed evenly over the cross-section of the reactor, and effect good axial mixing of the contents. Maintaining a well and thoroughly mixed condition is difficult because gases and liquids can separate unless they are traveling at the necessary speed such that they mix inherently. In commercial reactors, especially of the upflow variety where a relatively long residence time normally is required, the flow rates are such that separation of gas and liquid is quite significant. In certain instances, packing the vessels with inert materials is used to provide for the necessary mixing and to avoid separation of the gas and liquid. However, in spite of this, the chemical reactions often are not as uniform as may be desired.
In a number of processes which employ reactor vessels, there is a relatively large hold-up time for the gas and liquid which tends to cause them to separate. However, such hold-up time is often necessary to facilitate completion of the reaction. In this type of reactor, typically no packing of the catalyst bed is employed and the performance and operation of the distributor is particularly important. Prior art devices which have been employed in unpacked reactor vessels in order to mix and evenly distribute entering gas and liquid streams over substantially the entire cross-section of the vessel have included several different types of distributors or spargers. In a particular design the gas and liquid are mixed in a feed pipe or central header and then distributed through small holes in attached rings or lateral piping. The details of a typical distributor of this type can be found in U.S. Pat. No. 3,785,779. While this distributor is effective, it has certain disadvantages which include a substantial pressure drop in areas where the quench and main fluids are mixed and distributed and the holes in the sparger are easily plugged by suspended solids. Another problem is that stagnant regions can develop beneath or alongside the rings or the lateral pipes, that is, areas where substantially no flow occurs while gas and liquid collect. Another type of distributor which has been frequently used is where the gas and liquid are mixed in a so-called "quench" box. The fluids are distributed to the column or reactor after being deflected through a box which essentially comprises a small enclosed volume with few inlets and outlets in which fluid streams are mixed. While the latter design is less subject to fouling and requires relatively less pressure drop, the mixing and evenness of the gas liquid distribution is much poorer than the previously described distributor or that of the present invention. Also, the operation of the "quench" box is substantially affected by improper installation which may include tilting of the box or unsymmetrical flow into the box. Other distributors employed have included bubble caps for distributing the fluids; however, they require a relatively large pressure drop and do not properly mix the liquid and gas streams.